3D laser scanning is increasingly used in fire investigations to enable a multi-dimensional reproduction of the collected evidence, accessible to all stakeholders to explore and study time and again after the fact.
Fire incident investigators usually arrive at a very challenging scene: firefighters or emergency response crews may still be hard at work, the light may be fading or the weather turning and if the objects and materials involved aren’t hazardous, they are certainly fragile. While the type, scope and circumstance of a fire or arson scene investigation can vary drastically from case to case, all fire scenes are potentially hazardous for the investigator, all are liable to contamination and all must be measured and documented carefully for future study, whether this in the law court or the lab. These precise and reliable site measurements can look, on the one hand, like sketches, tape measures and camera photography or, on the other hand, like laser scanners, artificial intelligence and digital twins. In other words, a multi-dimensional reproduction of the collected evidence, accessible to all stakeholders to explore and study time and again after the fact.
Technological innovation equals better education
Robotic total stations, imaging laser scanners and drones have become in recent years increasingly important tools in the fire scene investigator’s toolbox. Technologies too, like virtual reality, have proven useful in training situations. Reality in Virtual Reality (RiVR), a developer of VR experiences in England, for example, creates immersive and educational training programmes for a variety of industries, including public safety. Using VR, they recreate crime and fire scenes that cannot be easily reproduced in real life, enabling students to immerse themselves in the details safely but to considerable educational effect.
Out with the old, in with the new
It’s a known challenge that forensic specialists must not only capture a wide range of rather complex, post-incident features of structural damage of a building and debris thoroughly but in a short time frame and all while navigating the complexities associated with safety on-site.
In post-explosion investigations, it is crucial to study the impact of shock waves, the severity of the damage and the direction of the falling debris. Without accurate documentation of the scene at first, these features are difficult, if not impossible, to observe in later investigative stages, and the chance of missing crucial evidence rises dramatically. In large-scale accidents, even the most experienced investigators can make mistakes and cannot fully ensure that every important observation is documented. It could be as simple as neglecting to measure some of the important details of the incident, whilst the site is being cleaned and reconstructed by the other parties involved. When humans are involved, so too is human error. Traditional methods, including image capturing using SLR cameras or the manual collection of evidence on the scene, can become hazardous, laborious and highly contagious due to limiting factors such as weather, light and radiation.
Terrestrial laser scanning technologies – fast and accurate scanning from a safe distance – have been of interest to the wider forensic engineering community, largely because they offer a countermeasure to some of the issues faced by every investigator.
Revisiting the scene
3D laser scanning can be utilised to document fire or arson incident scenes more inclusively, compared to traditional tools and methods of scene mapping and analysis. 3D laser scanners can easily capture fine details and spatial relationships with speed, comprehensiveness and 0.1-inch accuracy, regardless of environmental conditions and site range. Forensic software can integrate collected scan data directly with, for example, CCTV footage, images and other relevant documents into models for analysis and hypothesis. The results of the data analysis can be easily accessed from computers in the fire laboratory providing an easy and accessible way to refer to the details when needed. The fire event can be revisited weeks, months or years after the event by any interested party: lawyers, development associations, laboratory experts and police.
Investigating fire scenes in Dubai: a case study
Fire scenes are invariably complex and precarious, potentially dangerous and liable to contamination. Add into this mix adverse weather conditions, ultra-high humidity and temperatures, and dusty, smoky surroundings and you are imagining what it might be like to attend a fire scene investigation in Dubai. With its arid desert climate, Dubai is especially prone to fire outbreaks. In April 2023, 16 people were killed and nine injured after a fire broke out in an apartment block in Deira, one of the oldest parts of Dubai. In a city so vulnerable to fires, determining the cause of the breakout swiftly is essential so that regulators can adjust rules, policies or recommendations for subsequent incidents.
Major Mohammad A. Alqassim from the Dubai Police leads a team of forensic experts experienced in the investigation of fires, the analysis of evidence gathered and the effective use of the information produced by the investigation in the criminal justice system. Major Alqassim has been utilising various portable and stage-mounted 3D scanners for case investigations for many years, valuing how the implementation of new technologies in his team’s daily work can gather the most accurate results.
The key challenge for the police in Dubai is that adverse climate conditions can prevent investigators from completing their work as intended. Dubai Police was looking for a device that could cope with challenging surroundings and still deliver reliable results in wet and dry, hot and humid conditions.
While evidence gathering must not obstruct the movements of the firefighters and their patrols, every minute of delay in capturing the site may obscure crucial information for the investigation. Major Alqassim aims to obtain as much clean data as fast as possible using the 3D laser scanner. After completing the scans on-site, a technical expert registers and tags the data point cloud in the office and visualises the scan results.
Alqassim and his team selected the Leica RTC360 3D laser. Its features include VIS technology (Visual Inertial System), an enclosed mirror and full-time HDR photography. In addition, auto-calibration (‘check and adjust’) features of the device ensure consistent accurate measurements and the tagging feature allows for the integration of evidence photography, videography and witness testimony in 3D scans using Leica Cyclone FIELD 360 software. The double scan possibility in the laser scanner is a key feature which enables the investigator to capture ‘noiseless’ data without moving people or objects around the scene.
Alqassim and his team, along with public safety and forensic experts from Leica Geosystems, implemented this new technology to capture incidents and to deliver audio/visual scene reconstruction and reporting. Since early 2020, the forensic engineering team at the Dubai Police has been utilising the RTC360 to capture, map and analyse reported fire incidents. The team on the ground have found that the RTC360 reduces the time required on the scene to nearly half, compared with previous-generation scanners and mapping. Now, live 3D data visualisation and scanner tracking with the help of VIS technology enables investigators to capture scenes more easily and confidently. VIS also enables investigators to have auto-registered data onsite. Advanced image and video tagging, notations and on-site mobile app-based data registration in Cyclone FIELD 360 save valuable time in the office for the integration of point clouds, evidence images, tags and analysis with the investigation department’s mainframe databases.
3D laser scanning technology ensures that more investigations are successfully concluded through properly identifying, collecting and examining all relevant forensic evidence. In places with extreme weather or conditions that are likely to make the collection of evidence difficult, the laser scanner is proving an especially useful device. For forensic engineers in the Dubai Police Force, for example, the 3D laser scanner has proven to be the best-in-class tool used in fire scene documentation and analysis.
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